Directed Wireless Communication

ABSTRACT

In an implementation of directed wireless communication, a multi-beam directed signal system coordinates directed wireless communication with client devices. A transmit beam-forming network routes data communication transmissions to the client devices via directed communication beams that are emanated from an antenna assembly, and a receive beam-forming network receives data communication receptions from the client devices via the directed communication beams.

RELATED APPLICATION

This application claims the benefit of a related U.S. ProvisionalApplication Ser. No. 60/423,660, filed Nov. 4, 2002, entitled “AWireless Data Packet Communications System”, to Marcus da Silva et al.,which is incorporated by reference herein.

TECHNICAL FIELD

This invention relates to directed wireless communication.

BACKGROUND

Computing devices and other similar devices implemented to send and/orreceive data can be interconnected in a wired network or a wirelessnetwork to allow the data to be communicated between the devices. Wirednetworks, such as wide area networks (WANs) and local area networks(LANs) for example, tend to have a high bandwidth and can therefore beconfigured to communicate digital data at high data rates. One obviousdrawback to wired networks is that the range of movement of a device isconstrained since the device needs to be physically connected to thenetwork for data exchange. For example, a user of a portable computingdevice will need to remain near to a wired network junction to maintaina connection to the wired network.

An alternative to wired networks is a wireless network that isconfigured to support similar data communications but in a moreaccommodating manner. For example, the user of the portable computingdevice can move around within a region that is supported by the wirelessnetwork without having to be physically connected to the network. Alimitation of conventional wireless networks, however, is theirrelatively low bandwidth which results in a much slower exchange of datathan a wired network. Further, conventional wireless networks areimplemented with multiple base stations, or access points, that relaycommunications between wireless-configured devices. These conventionalaccess points have a limited communication range, typically 20 to 200feet, and a wireless network requires a large number of these accesspoints to cover and provide a communication link over a large area.

Many conventional wireless communication systems and networks implementomni-directional antennas to transmit data packets to a client deviceand receive data packets from or via an access point. With a standardwireless LAN, for example, a transmission is communicated equally in alldirections from an omni-directional antenna, or point of emanation.Receiving devices located within range and positioned at any angle withrespect to the emanating point can receive the wireless transmission.

However, standard omni-directional wireless LANs or omni-directionalwireless wide area networks (WANs) have drawbacks and limitations. Forexample, transmission range is limited and electromagnetic interferenceassociated with transmissions is unmanaged and can interfere with orotherwise restrict the use of other communicating devices that operatein the same frequency band within the transmission coverage area.Furthermore, inefficiencies and data corruption can occur if two or morecentralized points of emanation are positioned proximate to haveoverlapping coverage areas.

SUMMARY

Directed wireless communication is described herein.

In an implementation, a multi-beam directed signal system coordinatesdirected wireless communication with client devices. A transmitbeam-forming network routes data communication transmissions to theclient devices via directed communication beams that are emanated froman antenna assembly, and a receive beam-forming network receives datacommunication receptions from the client devices via the directedcommunication beams.

BRIEF DESCRIPTION OF THE DRAWINGS

The same numbers are used throughout the drawings to reference likefeatures and components.

FIG. 1 illustrates an exemplary wireless communications environment.

FIG. 2 illustrates an exemplary directed wireless communication system.

FIG. 3 illustrates an exemplary communication beam array which can begenerated with the exemplary directed wireless communication systemshown in FIG. 2.

FIG. 4 illustrates an exemplary antenna array for an antenna assembly asshown in FIG. 3.

FIG. 5 illustrates an exemplary implementation of the directed wirelesscommunication system shown in FIG. 2.

FIG. 6 illustrates an exemplary set of communication beams that emanatefrom an antenna array of an antenna assembly as shown in FIG. 3.

FIG. 7 illustrates an exemplary multi-beam directed signal system thatestablishes multiple access points.

FIGS. 8A and 8B illustrate various components of a multi-beam directedsignal system and an antenna assembly of the directed wirelesscommunication system shown in FIG. 2.

FIG. 9 illustrates an exemplary multi-beam directed signal system thatincludes various components such as medium access controllers (MACs),baseband units, and MAC coordinator logic.

FIG. 10 further illustrates various components of the exemplarymulti-beam directed signal system shown in FIG. 9.

FIG. 11 illustrates a state transition diagram for a medium accesscontroller (MAC).

FIG. 12 illustrates a multi-beam directed signal system receiving andweighting various communication signals.

FIG. 13 illustrates an exemplary multi-beam directed signal system thatincludes various component implementations.

FIG. 14 further illustrates a component implementation of the multi-beamdirected signal system for complementary beam-forming.

FIG. 15 illustrates a graph depicting a signal level output (dB) for thecomponent implementation shown in FIG. 14.

FIG. 16 illustrates a state transition diagram for a roaming clientdevice in wireless communication with a multi-beam directed signalsystem as shown in FIG. 2.

FIG. 17 is a flow diagram of an exemplary method for a directed wirelesscommunication system implemented with a multi-beam directed signalsystem and antenna assembly.

FIG. 18 is a flow diagram of an exemplary method for a directed wirelesscommunication system implemented with a multi-beam directed signalsystem and antenna assembly.

FIG. 19 is a flow diagram of an exemplary method for client deviceroaming in a directed wireless communication system.

DETAILED DESCRIPTION

Directed wireless communication is described in which a multi-beamdirected signal system is implemented to communicate over a wirelesscommunication link via an antenna assembly with client devicesimplemented for wireless communication within the wireless system. Thedirected wireless communication system can be implemented to communicatewith multiple devices, such as portable computers, computing devices,and any other type of electronic and/or communication device that can beconfigured for wireless communication. Further, the multiple electronicand/or computing devices can be configured to communicate with oneanother within the wireless communication system. Additionally, adirected wireless communication system can be implemented as a wirelesslocal area network (WLAN), a wireless wide area network (WAN), awireless metropolitan area network (MAN), or as any number of othersimilar wireless network configurations.

The following description identifies various systems and methods thatmay be included in such directed wireless communication systems andnetworks. It should be noted, however, that these are merely exemplaryand that not all of the techniques described herein need be implementedin a given wireless system or network. Furthermore, many of theexemplary systems and methods described herein are also applicableand/or adaptable for use in other communication systems and networks.

Directed wireless communication provides improved performance overconventional wireless network arrangements by utilizing multi-beamreceiving and/or transmitting adaptive antennas, when practical. In animplementation, simultaneous transmission and reception may occur at awireless routing device by applying multi-channel techniques. In adescribed implementation, a multi-beam directed signal system (e.g.,also referred to as an access point or Wi-Fi switch) is a long-rangepacket switch designed to support 802.11b clients in accordance with an802.11 standard. An increase in communication range is achieved bybeam-forming directed communication beams which simultaneously transmitdirected signals and receive communication signals from differentdirections via receive and transmit beam-forming networks.

The multi-beam directed signal system establishes multiplepoint-to-point links (e.g., directed communication beams) by which datapackets can be communicated. The point-to-point links have acommunication range that covers a much larger area than conventionalaccess points, eliminating the need for multiple communication accesspoints and significantly reducing the complexity and cost of a wirelessLAN (WLAN) network. Further, a client device can use a conventionalwireless card to communicate with the multi-beam directed signal systemover long distances with no modification of the client device.Accordingly, directed wireless communication as described hereinrepresents a significant improvement over conventional wireless networksthat use switched beam and/or omni-directional antennas.

FIG. 1 illustrates an exemplary wireless communications environ merit100 that is generally representative of any number of different types ofwireless communications environments, including but not limited to thosepertaining to wireless local area networks (LANs) or wide area networks(WANs) (e.g., Wi-Fi compatible) technology, cellular technology,trunking technology, and the like. In wireless communicationsenvironment 100, an access station 102 communicates with remote clientdevices 104(1), 104(2), . . . , 104(N) via wireless communication orcommunication links 106(1), 106(2), . . . , 106(N), respectively.Although not required, access station 102 is typically fixed, and remoteclient devices 104 may be fixed or mobile. Although only three remoteclient devices 104 are shown, access station 102 can wirelesslycommunicate with any number of different client devices 104.

A directed wireless communication system, Wi-Fi communication system,access station 102, and/or remote client devices 104 may operate inaccordance with any IEEE 802.11 or similar standard. With respect to acellular system, for example, access station 102 and/or remote clientdevices 104 may operate in accordance with any analog or digitalstandard, including but not limited to those using time division/demandmultiple access (TDMA), code division multiple access (CDMA), spreadspectrum, some combination thereof, or any other such technology.

Access station 102 can be implemented as a nexus point, a trunkingradio, a base station, a Wi-Fi switch, an access point, some combinationand/or derivative thereof, and so forth. Remote client devices 104 maybe, for example, a hand-held device, a desktop or laptop computer, anexpansion card or similar that is coupled to a desktop or laptopcomputer, a personal digital assistant (FDA), a mobile phone, a vehiclehaving a wireless communication device, a tablet or hand/palm-sizedcomputer, a portable inventory-related scanning device, any devicecapable of processing generally, some combination thereof, and the like.Further, a client device 104 may be any device implemented to receiveand/or transmit information (e.g., in the form of data packets) via theapplicable wireless communication links 106. Remote client devices 104may also operate in accordance with any standardized and/or specializedtechnology that is compatible with the operation of access station 102.

FIG. 2 illustrates an exemplary directed wireless communication system200 that can be implemented in any form of a wireless communicationsenvironment 100 as described with reference to FIG. 1. The directedwireless communication system 200 includes an access station 102 andremote client devices 202 and 204. The access station 102 includes amulti-beam directed signal system 206 coupled to an antenna assembly 208via a communication link 210. In this example implementation, accessstation 102 is coupled to an Ethernet backbone 212.

The antenna assembly 208 can be implemented as two or more antennas, andoptionally as a phased array of antenna elements, to emanate multipledirected communication beams 214(1), 214(2), . . . , 214(N). The antennaassembly 208 is an unobtrusive indoor or outdoor Wi-Fi antenna panelthat can include various operability components such as RF devices andcomponents, a central processing unit, a power supply, and other logiccomponents. The antenna assembly can be implemented as a lightweight andthin structure that can be mounted on a wall or in a corner of a room toprovide wireless communication over a broad coverage area, such asthroughout a building and surrounding area, or over an expanded region,such as a college campus or an entire corporate or manufacturingcomplex. While the antenna assembly may be applicable or adaptable foruse in many other communication systems, the antenna assembly isdescribed in the context of an exemplary wireless communicationsenvironment 100 (FIG. 1).

The multi-beam directed signal system 206 can transmit and/or receive(i.e., transceive) information (e.g., in the form of data packets) byway of one or more directed communication beams 214 as a wirelesscommunication via the antenna assembly 208. Additionally, wirelesscommunication(s) are transmitted and/or received from (i.e., transceivedwith respect to) a remote client device, such as client devices 202 and204. The wireless communications may be transceived directionally withrespect to one or more particular communication beams 214. Themulti-beam directed signal system 206 can be implemented formulti-channel directed wireless communication. For example, clientdevice 202 can communicate via directed communication beam 214(1) with afirst channel of the multi-beam directed signal system 206, and clientdevice 204 can communicate via directed communication beam, 214(N) witha second channel of the multi-beam directed signal system 206.

In the exemplary directed wireless communication system 200, signals maybe sent from a transmitter to a receiver using electromagnetic wavesthat emanate from one or more antenna elements of the antenna assembly208 which are focused in one or more desired directions. For example,the multi-beam directed signal system generates a directed wirelesscommunication for transmission to wireless client device 202 viadirected communication beam 214(1). This is in contrast to conventionalomni-directional transmission systems that transmit a communication inall directions from an omni-directional antenna (e.g., exampleomni-directional transmission area 216 emanating from a centraltransmission point with reference to antenna assembly 208 and shown onlyfor comparison). Although not to scale, the illustration depicts thatthe power to transmit over the omni-directional transmission area 216can be directed as one or more communication beams over a fartherdistance 218 from a point of transmission (e.g., antenna assembly 208).

When the electromagnetic waves are focused in a desired direction, thepattern formed by the electromagnetic wave is termed a “beam” or “beampattern”, such as a directed communication beam 214. The productionand/or application of such electromagnetic beams 214 is typicallyreferred to as “beam-forming.” Beam-forming provides a number ofbenefits such as greater range and/or coverage per unit of transmittedpower, improved resistance to interference, increased immunity to thedeleterious effects of multi-path transmission signals, and so forth.For example, a single communication beam 214(1) can be directed forcommunication with a specific wireless-configured client device 202 andcan be transmitted over a much greater distance 218 than would becovered by a conventional omni-directional antenna (e.g., exampleomni-directional transmission area 216 shown only for comparison).

FIG. 3 illustrates an exemplary communication beam array 300 of directedcommunication beams 214(1), 214(2), . . . , 214(N) that emanate from anantenna array 302 which is part of the antenna assembly 208. Antennaassembly 208 is also referred to herein as an “adaptive antenna” whichdescribes an arrangement that includes the antenna array 302 having aplurality of antenna elements, and operatively supporting mechanismsand/or components (e.g., circuits, logic, etc.) that are part of awireless routing device and configured to produce a transmission patternthat selectively places transmission nulls and/or peaks in certaindirections within an applicable coverage area.

A transmission peak of a directed communication beam 214 occurs in thetransmission pattern 300 when a generated and particular amount ofenergy is directed in a particular direction. Transmission peaks are,therefore, associated with the signal path and/or communication beam toa desired receiving node, such as another wireless routing device or awireless client device. In some cases, sidelobes to a communication beammay also be considered to represent transmission peak(s).

Conversely, a transmission null (e.g., not a communication beam) occursin the transmission pattern when no transmission of energy occurs in aparticular direction, or a relatively insignificant amount of energy istransmitted in a particular direction. Thus, a transmission null isassociated with a signal path or lack of a communication beam towards anundesired, possibly interfering, device and/or object. Transmissionnulls may also be associated with the intent to maximize power inanother direction (i.e., associated with a transmission peak), toincrease data integrity or data security, and/or to save power, forexample. A determination to direct a transmission null and/or atransmission peak (e.g., a communication beam 214) in a particulardirection can be made based on collected or otherwise provided routinginformation which may include a variety of data associated with theoperation of the multi-beam directed signal system 206, wireless routingdevice, and other devices at other locations or nodes within thewireless network.

One or more of the communication beams 214(1), 214(2), . . . , 214(N)are directed out symmetrically from antenna array 302 to communicateinformation (e.g., in the form of data packets) with one or morewireless client devices. The communication beam array 300 shown in FIG.3 is merely exemplary and other communication beam arrays, or patterns,may differ in width, shape, number, angular coverage, azimuth, and soforth. Further, although all of the directed communication beams 214 areshown emanating from antenna array 302 at what would appear as a sametime, transmission and reception via one or more communication beams 214is controlled and coordinated with signal control and coordination logic304 of the multi-beam directed signal system 206.

The signal control and coordination logic 304 can monitor each of thedirected communication beams 214 as an individual access point. Further,the signal control and coordination logic 304 can control a directedwireless transmission to a first client device and a directed wirelesstransmission from a second client device such that the directed wirelesstransmission does not interfere with the directed wireless reception.Optionally, a directed wireless transmission and a directed wirelessreception can be simultaneous.

As used herein, the term “logic” (e.g., signal control and coordinationlogic 304) refers to hardware, firmware, software, or any combinationthereof that may be implemented to perform the logical operationsassociated with a given task. Such, logic can also include anysupporting circuitry that may be required to complete a given taskincluding supportive non-logical operations. For example, “logic” mayalso include analog circuitry, memory, input/output (I/O) circuitry,interface circuitry, power providing/regulating circuitry, etc.

The directed communication beams 214 of antenna array 302 can bedirectionally controllable, such as steerable in an analogimplementation or stepable in a digital implementation. For example, adirected communication beam 214 can be directionally stepable by thewidth (e.g., degrees) of the communication beam to “steer” or “aim”addressable data packets when communicating with a client device.Further, a communication beam 214 can be directionally controllable suchthat only an intended client device will receive a directed wirelesscommunication via the communication beam 214, and such that anunintended recipient will not be able to receive the directed wirelesscommunication.

Although data signals (e.g., information as data packets) can bedirected to and from a particular client device (e.g., client devices202 and 204) via one or more directed communication beams 214,interference between communications beams 214 can occur. For example, adownlink signal transmission from antenna assembly 208 via communicationbeam 214(2) can corrupt an uplink signal reception at antenna assembly208 via communication beam 214(3). The signal control and coordinationlogic 304 coordinates uplink and downlink signal transmissions across(e.g., between and/or among) the different communication beams 214 so asto avoid, or at least reduce, the frequency at which downlink directedsignals are transmitted via a first communication beam (e.g.,communication beam 214(2)) while uplink directed signals are beingreceived via a second communication beam (e.g., communication beam214(3)).

FIG. 4 illustrates an exemplary antenna array 302 (also referred toherein as an adaptive antenna) that is formed with an array of antennaelements 400. Each antenna element 400 has multiple communication signaltransfer slots 402 (e.g., transfer slots 402(1) and 402(2)) that areformed into a front surface 404 of an antenna element 400. The antennaarray 302 transmits and receives data as electromagnetic communicationsignals via the transfer slots 402 in each antenna element 400.

In an exemplary implementation, the communication signal transfer slots402 in an antenna element 400 are formed into two parallel slot rows406(1) and 406(2) in which the transfer slots 402(1) in slot row 406(1)are staggered, or otherwise offset, in relation to the transfer slots402(2) in slot row 406(2). Each transfer slot 402(1) in slot row 406(1)is offset from each transfer slot 402(2) in slot row 406(2) in adirection 408 and a distance 410. For example, transfer slot 402(1) inslot row 406(1) is offset from transfer slot 402(2) in slot row 408(2)in a direction that is parallel to the slot rows 406 (e.g., thedirection 408) over a distance that is approximately the length of onerectangular transfer slot 402 (e.g., the distance 410). The distance 410between transfer slots 402 in a slot row 406 is approximately theantenna element wavelength λ_(g)/2 apart.

The gain of an adaptive antenna (e.g., antenna array 302) is dependenton the implementation of the multi-beam directed signal system 206.However, for a uniformly illuminated antenna array, the antenna gain isrelated to its effective aperture by an equation:

$G_{R} = \frac{4\; {\pi \cdot A_{eff}}}{\lambda^{2}}$

Assuming A_(eff) is equal to a cross-sectional area of the antennaarray:

$G_{R} = \frac{4\; {\pi \cdot w \cdot h}}{\lambda^{2}}$

where w is the width of the antenna, h is the height of the antenna, andλ is the wavelength. For an example indoor implementation of an antennaarray where w=8λ and h=4λ, the antenna gain is determined by theequation:

$G_{R} = {\frac{4\; {\pi \cdot 8}\; {\lambda \cdot 4}\; \lambda}{\lambda^{2}} = {{128\; \pi} = {26\mspace{14mu} {dB}\; i}}}$

For an example outdoor implementation of an antenna array where w=8λ andh=8λ, the antenna gain is determined by the equation:

$G_{R} = {\frac{4\; {\pi \cdot 8}\; {\lambda \cdot 8}\; \lambda}{\lambda^{2}} = {{256\; \pi} = {29.1\mspace{14mu} {dB}\; i}}}$

When dissipation losses are zero, the antenna gain is equivalent todirectivity. The effective aperture may include the effect of losses,and therefore the formulas may be used to calculate the gain. When theactual dimensions of the antenna array 302 are used as the “effectivearea”, the losses are assumed to be zero (e.g., for an idealimplementation).

In this example illustration, the antenna array 302 is shown configuredfor indoor use with sixteen antenna elements (e.g., sixteen of antennaelements 400 formed or otherwise positioned together) each having twoparallel rows of four communication signal transfer slots each (e.g.,slot rows 406(1) and 406(2)). The antenna array 302 can be configuredfor outdoor use with thirty-two antenna elements (e.g., multiple antennaelements 400) each having two parallel rows of eight communicationsignal transfer slots each, or can be configured as a larger antennaarray or antenna panel with more antenna elements having morecommunication signal transfer slots per slot row. The antenna array 302can be configured with as many antenna elements 400 having any number oftransfer slots 402 per slot row 406 as needed to provide communicationsignal transfer (e.g., wireless communication) over a region or desiredcoverage area.

FIG. 5 illustrates an exemplary implementation 500 of a directedwireless communication system (e.g., directed wireless communicationsystem 200 shown in FIG. 2) that includes antenna assembly 208 andantenna array 302 as shown in FIG. 4. In this example, antenna array 302is positioned outside of a building 502 and mounted on an adjacentbuilding 504 to provide wireless communication throughout building 502and throughout a region 506 outside of building 502. The antenna array302 is coupled to the multi-beam directed signal system 206 (FIG. 2)which can be communicatively coupled via a LAN connection, for example,to a server computing device positioned in building 504. The servercomputing device can be implemented to administrate and control theassociated functions and operations of the directed wirelesscommunication system 200. Alternatively, antenna array 302 can bemounted within building 502 to provide wireless communication throughoutbuilding 502 and throughout the region 506 outside of building 502. Forexample, antenna array 302 can be mounted in a corner between twointerior perpendicular walls to provide wireless communication coveragethroughout the coverage area (e.g., building 502 and region 506 outsideof the building).

The directed wireless communication system 200 (e.g., shown inimplementation 500) provides wireless communication of information(e.g., in the form of data packets) via directed communication beams508(1), 508(2), . . . , 508(N) to any number of electronic and/orcomputing client devices that are configured to recognize and receivetransmission signals from the antenna array 302. Any one or more of theelectronic and computing client devices may also transmit informationvia the directed communication beams 508. Such electronic and computingdevices can include printing devices, desktop and portable computingdevices such as a personal digital assistant (PDA), cellular phone, andsimilar mobile communication devices, and any other type of electronicdevices configured for wireless communication connectivity throughoutbuilding 502, as well as portable devices outside of building 502, suchas computing device 510 within region 506. One or more of the electronicand computing client devices may also be connected together via a wirednetwork and/or communication link.

FIG. 6 illustrates an exemplary set or array of communication beams 600that emanate from an antenna array 302 as shown in FIGS. 3 and 4. In adescribed implementation, antenna array 302 can include sixteen antennaelements 400(0, 1, . . . , 14, and 15) (not explicitly shown in FIGS. 4and 6). From the sixteen antenna elements 400(0-15), sixteen differentcommunication beams 602(0), 602(1), . . . , 602(15) are formed as thewireless communication signals emanating from antenna elements 400(0-15)which may add and/or subtract from each other during electromagneticpropagation.

Communication beams 602(1), 602(15) spread out, or are directed out,symmetrically from a central communication beam 602(0). The narrowestbeam is the central beam 602(0), and the beams become wider as theyspread outward from the central beam. For example, beam 602(15) adjacentbeam 602(0) is slightly wider than beam 602(0), and beam 602(5) is widerthan beam 602(15). Also, beam 602(10) is wider still than beam 602(5).The communication beam pattern of the set of communication beams 600illustrated in FIG. 6 are exemplary only and other communication beampattern sets may differ in width, shape, number, angular coverage,azimuth, and so forth.

Due to implementation effects of the interactions between and among thewireless signals as they emanate from antenna array 302 (e.g., assuminga linear antenna array in a described implementation), communicationbeam 602(8) is degenerate such that its beam pattern is formed on bothsides of antenna array 302. These implementation effects also accountfor the increasing widths of the other beams 602(1-7) and 602(15-9) asthey spread outward from the central communication beam 602(0). Inaddition to the implementation effects of the interactions between andamong the wireless signals, an obliquity effect explains that an azimuthbeamwidth is related to the projected horizontal dimension of the array,as viewed from an oblique angle. Accordingly, the array appears narrowerwhen viewed from an oblique angle, and therefore has a wider beamwidthas compared to a beamwidth viewed from a perpendicular angle. Beamwidthand directivity are inversely proportional and an obliquity factor(i.e., cos(azimuth angle)) defines a reduction in antenna arraydirectivity at oblique angles and thus an increase in beamwidth. In afurther implementation, communication beams 602(7) and 602(9) may be toowide for efficient and productive use. Hence, communication beams602(7), 602(8), and 602(9) are not used and the implementation utilizesthe remaining thirteen communication beams 602 (e.g., communicationbeams 602(0-6) and beams 602(10-15)).

FIG. 7 illustrates an exemplary implementation 700 of the multi-beamdirected signal system 206 which establishes multiple access points702(1), 702(2), 702(N). The multi-beam directed signal system 206establishes any number access points 702 which can each correspond to,for example, an individual access point in accordance with an IEEE802.11-based standard. Additionally, a wireless coverage area or regionfor each respective access point 702 may correspond to, for example, arespective directed communication beam 214 as shown in FIGS. 2 and 3, ora respective communication beam 602 as shown in FIG. 6.

Although communication signals directed into (or obtained from)different access points 702 may be directed at particular or specificcoverage areas, interference between access points 702 can occur. Forexample, a downlink signal transmission for access point 702(2) candestroy an uplink signal reception for access point 702(1). Generally,signal control and coordination logic 304 coordinates uplink signalreceptions and downlink signal transmissions across (e.g., betweenand/or among) different access points 702 so as to avoid, or at leastreduce, the frequency at which downlink signals are transmitted at afirst access point while uplink signals are being received at a secondaccess point.

Specifically, signal control and coordination logic 304 is adapted tomonitor the multiple access points 702(1), 702(2), . . . , 702(N) toascertain when a signal, or communication of information, is beingreceived. When an access point 702 is ascertained to be receiving asignal, the signal control and coordination logic 304 limits (e.g.,prevents, delays, etc.) the transmission of signals on the other accesspoints 702 such that signal transmission does not interfere with signalreception. The monitoring, ascertaining, and restraining of signals canbe based on and/or responsive to many factors. For example, the signalscan be coordinated (e.g., analyzed and controlled) based on aper-channel basis.

FIGS. 8A and 8B illustrate various components of the multi-beam directedsignal system 206 and the antenna assembly 208 both shown in FIGS. 2 and3. FIG. 8A illustrates antenna array 302 which includes the sixteenantenna elements 400(0, 1, . . . , 15) as described with reference toFIG. 6. The antenna assembly 208 includes RF (radio frequency)components which are shown as a left transmit antenna board 800, a righttransmit antenna board 802, a left receive antenna board 804, and aright receive antenna board 806. The multi-beam directed signal system206 includes a transmit beam-forming network 808 and a receivebeam-forming network 810.

The left transmit antenna board 800 includes transmission logic 812(0,1, 7) and the right transmit antenna board 802 includes transmissionlogic 812(8, 9, . . . , 15). Each transmission logic 812 (e.g., circuit,component, etc.) corresponds to an antenna element 400(0-15) of theantenna array 302 and corresponds to a signal connection (e.g., node,port, channel, etc.) of the transmit beam-forming network 808(0-15).Similarly, the left receive antenna board 804 includes reception logic814(0, 1, . . . , 7) and the right receive antenna board 806 includesreception logic 814(8, 9, 15). Each reception logic 814 (e.g., circuit,component, etc.) corresponds to an antenna element 400(0-15) of theantenna array 302 and corresponds to a signal connection (e.g., node,port, channel, etc.) of the receive beam-forming network 810(0-15).

Generally, a beam-forming network 808 and 810 may include multiple portsfor connecting to antenna array 302 and multiple ports for connecting tothe multiple RF components, such as the transmit and receive antennaboards 800-806. One or more active components (e.g., a power amplifier(PA), a low-noise amplifier (LNA), etc.) may also be coupled to themultiple ports on the antenna array side of a beam-forming network.Thus, antenna array 302 may be directly or indirectly coupled to abeam-forming network 808 and 810.

Specifically, a beam-forming network 808 and 810 may include at least“N” ports for each of the multiple RF transmission and receive logiccomponents 812 and 814, respectively. For example, each directedcommunication beam 214 (FIG. 2) or 602 (FIG. 6) emanating from antennaarray 302 corresponds to an RF logic component 812 and/or 814. Each RFlogic component 812 and 814 can be implemented as, for example, atransmit and/or receive signal processor operating at one or more radiofrequencies, with each frequency corresponding to a different channel.It should be noted that channels may be defined alternatively (and/oradditionally) using a mechanism other than frequency, such as a code, atime slot, some combination thereof, and so forth.

FIG. 8B further illustrates various components of the multi-beamdirected signal system 206 which includes the signal control andcoordination logic 304, a multi-beam controller 816, one or more memorycomponents 818, communication interface(s) 820, a scanning receiver 822,and receiver/transmitters (Rx/Tx) 824(0, 1, . . . , 15). The multi-beamcontroller 816 (e.g., any of a processor, controller, logic, circuitry,etc.) can be implemented to control channel assignments forcommunication signals and data communication coordinated by the signalcontrol and coordination logic 304.

The channel assignments coordinated by the signal control andcoordination logic 304 provides the best channel assignment for a signalbased on given measurement information. Parameters of a channelassignment algorithm include:

-   -   ChannelAssignmentCycle which identifies a duration between        changes in the channel assignment;    -   HeavyInterference which identifies an interference activity        threshold. If, for example, interference activity is determined        to be above this value, a particular channel may be considered        deficient for the duration of time that the interference can be        detected;    -   BadChannelThreshold which identifies a number of measurement        periods (e.g., a MeasurementDuration) that a channel has        interference activity above the HeavyInterference threshold; and    -   JamInterference which identifies an interference activity        threshold above the HeavyInterference parameter.        Further, channel assignment internal parameters can include:    -   MeasurementCycle which identifies a time duration (e.g.,        twenty-four hours) in which a measurement is completed;    -   MeasurementDuration which identifies a time duration (e.g.,        minutes) between two measurement points;    -   PeakLoadLimit which identifies a maximum load allowed on one        channel; and    -   ChannelSixBiasFactor which is a bias factor to compensate for        transmission on channel six to reduce inter-modulation.

The scanning receiver 822 and the receiver/transmitters (Rx/Tx) 824measure metrics of channel activity every specified MeasurementDurationduring a cycle of MeasurementCycle. The metrics can include a number ofassociated client devices, throughput and packet error rates (PER) ofeach receiver/transmitter 824, interference and channel utilization ofeach communication beam (e.g., frequency, or channel), and/or any numberof other metrics. The channel activity metrics include:

-   -   N_(i)(t) which is a number of associated clients of the ith        Rx/Tx 824 and which is averaged over the MeasurementDuration        period;    -   S_(i)(t) which is the throughput of the ith Rx/Tx 824 measured        in packets/second or bytes/second, and which is averaged over        the MeasurementDuration period;    -   P_(i)(t) which is a packet error rate (PER) of the ith Rx/Tx 824        and which is averaged over the MeasurementDuration period;    -   D_(i)(t) which is a delay of the ith Rx/Tx 824 and which is        averaged over the MeasurementDuration period;    -   ρ_(i)(t) which is channel utilization of the ith beam on the jth        channel and which is measured by both the Rx/Tx 824 and scanning        receiver 822 and averaged over the MeasurementDuration period.        This is also referred to as a Channel Utilization Factor (CUF);    -   Ns_(j)(t) which is a number of downlink data packets transmitted        on the jth channel and which is averaged over the        MeasurementDuration period;    -   Nr_(ij)(t) which is a number of correctly received uplink data        packets transmitted by client devices associated with the ith        beam on the jth channel, and which is averaged over the        MeasurementDuration period;    -   Nn_(ij)(t) which is a number of uplink data packets transmitted        by client devices associated with other communication beams, and        which are correctly received by the ith beam on the jth channel.        This is measured by the scanning receiver 822 and is averaged        over the MeasurementDuration period. This is also referred to as        the Self Interference Metric (SIM);    -   No_(ij)(t) which is a number of uplink data packets transmitted        by the client devices from overlapping subnets and which are        correctly received by the ith beam on the jth channel. This is        measured by the scanning receiver 822 and is averaged over the        MeasurementDuration period. This is also referred to as the        Overlapping Subnet Interference (OSI);    -   Ne_(ij)(t) which is a number of uplink data packets with PLCP or        data CRC errors in the ith beam on the jth channel and which is        measured by the scanning receiver 822 and averaged over the        MeasurementDuration period. This is also referred to as the        Unidentified Interference Metric (UIM); and    -   I_(ij)(t) which is the interference of the ith beam on the jth        channel and which is measured by the scanning receiver 822.        These and other metrics can be maintained with a memory        component 818 in a data table (or similar data construct) within        the MeasurementCycle. When the cycle restarts, the data table        can either be cleared or updated with some aging factor to        identify past metrics.

The metric I_(ij)(t) can be derived from other measurements when thereceiver/transmitters 824 are on the same channel. In such cases,I_(ij)(t) can be estimated by first estimating a total number of packetsfrom any overlapping subnets by an equation:

${{NI}_{ij}(t)} = {{{No}_{ij}(t)} + {{{Ne}_{ij}(t)} \cdot \frac{{No}_{ij}(t)}{{{Nr}_{ij}(t)} + {{Nn}_{ij}(t)} + {{No}_{ij}(t)}}}}$

Further, I_(ij)(t) may be estimated by:

${I_{ij}(t)} = {\frac{{NI}_{ij}(t)}{{{NS}_{i}(t)} + {{Nr}_{ij}(t)} + {{Nn}_{ij}(t)} + {{No}_{ij}(t)} + {{Ne}_{ij}(t)}} \cdot \rho_{ij}}$

For channel assignment pre-processing, a channel that has interferenceactivity which exceeds HeavyInterference for a BadChannel Threshold isnot used. The interference activity is averaged over intervals of theMeasurementDuration period. In an implementation, a MeasurementCycle caninclude forty-eight measurement intervals. A channel can be eliminatedif the interference activity HeavyInterference exceeds theBadChannelThreshold for a specified number of periods.

The total number of active users (e.g., client devices) associated withany one directed communication beam 214 (FIG. 2) or 602 (FIG. 6) can beestimated by dividing the number of associated users of thatcommunication beam by the percentage of time available to those users.The total number of users on beam i and channel j may therefore bedescribed by:

${N_{ij}(t)} = \frac{N_{i}(t)}{1 - {{{}_{}^{}{}_{}^{}}(t)}}$

where ^(˜)I_(ij)(t)=min {I_(ij)(t), HeavyInterference} which is theinterference activity limited to a maximum allowable interference on agiven communication beam. This ensures that the estimate does notprovide large peaks due to an unusual period of high interference.

A block-based channel assignment algorithm assigns adjacentcommunication beams to the same frequency channel which minimizes thehidden beam problem as described further with reference to FIG. 14. Thealgorithm allocates the thirteen communication beams into a maximum ofthree blocks, with each block assigned to one frequency channel (e.g.,channels 1, 6, or 11) so that the peak load on each channel isminimized. To determine an optimal solution, the boundaries between theassignment blocks (i.e. the number of communication beams in each block)and the frequency channel of each block is determined.

There are sixty-six possible combinations that divide thirteencommunication beams into three blocks. For each of these possiblecombinations, the three blocks would be assigned to the three differentchannels. The number of channel permutations is six and the bestchannel-beam combination from three hundred, ninety-six (66×6=396)possible combinations can be determined. A factor L_(j)(t) is denoted asthe total load on the jth frequency channel at time (t) such that.L_(j)*=max {L_(j)(t)} where t is of the set [0,T] which is the peak loadon the jth channel in the last measurement period, and where T is themeasurement cycle (i.e., MeasurementCycle). A combination can bedetermined that minimizes the peak load on all of the channels which canbe described as min {max {L_(j)*}} where j is of the set [f₁,f₆,f₁₁].

In an event that the overall network communication load, or traffic, isminimal, fewer than the three frequency channels may be used. Aparameter PeakLoadLimit identifies a communication load limit belowwhich only two of the frequency channels (e.g., channel 1 and channel11, for example) are used. If the peak communication load on either ofthe two channels exceeds the PeakLoadLimit, then the three frequencychannels can be utilized.

The block-based channel assignment algorithm can be implemented toutilize two or three frequency channels. Initially, the thirteencommunication beams are divided into two blocks of which there aretwelve possible combinations. For each combination, the channelselections can be f₁f₆, f₁f₁₁, f₆f₁, f₆f₁₁, f₁₁f₁; or f₁₁f₆ such thatthere are a total of seventy-two block and channel combinations.Assuming that the kth block-channel combination has a configuration asfollows:

-   -   Block 1: communication beams 0 to b (0 to N−2) are assigned to        channel C₁; and    -   Block 2: communication beams b_(k)+1 to N−1 (1 to N−1) are        assigned to channel C₂        Then the communication traffic load of channels C₁ and C₂ are:

${L_{\; {C\; 1}}^{ki}(t)} = {\sum\limits_{i = 0}^{b_{k}}{N_{i\; C\; 1}(t)}}$${L_{C\; 2}^{k}(t)} = {\sum\limits_{i = {b_{k} + 1}}^{N - 1}{N_{i\; C\; 2}(t)}}$

The peak communication load on the first block for combination k isdenoted by:

PL ₁(k)=max {L ^(k) _(C1)(t)} where t is of the set [0,T]

PL ₂(k)=max {L ^(k) _(C2)(t)} where t is of the set [0,T],

and the peak communication load for the busiest block (e.g., channel is:

PL _(max)(k)=max {PL ₁(k),PL ₂(k)}

A combination index R with the least peak communication load is thenselected such that PL_(max)(R)=min {PL_(max)(k)} where (0≦k≦71) which isthe combination of channels and beams that minimize the peak load on anychannel. If the peak load on a channel is not less than thePeakLoadLimit, then a three channel assignment can be implemented.Initially, the thirteen communication beams are divide into three blocksof which there are sixty-six possible combinations. For eachcombination, the channel selections can be f₁f₆f₁₁, f₁f₁₁f₆, f₆f₁f₁₁,f₆f₁₁f₁, f₁₁f₁f₆, or f₁₁f₆f₁ such that there are a total ofthree-hundred, ninety-six block and channel combinations. Assuming thatthe kth block-channel combination has a configuration as follows:

-   -   Block 1: communication beams 0 to b_(k) (0 to N−3) are assigned        to channel C₁; and    -   Block 2: communication beams b_(k)+1 to p_(k) (1 to N−2) are        assigned to channel C₂; and    -   Block 3: communication beams p_(k)+1 to N−1 (2 to N−1) are        assigned to channel C₃;        Then the communication traffic load of channels C₁, C₂, and C₃        are:

${L_{\; {C\; 1}}^{ki}(t)} = {\sum\limits_{i = 0}^{b_{k}}{N_{i\; C\; 1}(t)}}$${L_{C\; 2}^{k}(t)} = {\sum\limits_{i = {b_{k} + 1}}^{p_{k}}{N_{i\; C\; 2}(t)}}$$L_{C\; 3}^{k} = {\sum\limits_{i = {p_{k} + 1}}^{N - 1}{N_{i\; C\; 3}(t)}}$

The peak communication load on the first block for combination k isdenoted by:

PL ₁(k)=max {L ^(k) _(C1)(t)} where is of the set [0,T]

PL ₂(k)=max {L ^(k) _(C2)(t)} where t is of the set [0,T],

PL ₃(k)=max {L ^(k) _(C3)(t)} where t is of the set [0,T],

and the peak communication load for the busiest block (e.g., channel)is:

PL _(max)(k)=max {PL ₁(k),PL ₂(k),PL ₂(k)}

A combination index R with the least peak communication load is thenselected such that PL_(max)(R)=min {PL_(max)(k)} where (0≦k≦395) whichis the combination of channels and beams that minimize the peak load onany channel.

When taking into account intermodulation such that channel combinationsf₁f₆ and f₆f₁₁ are to be avoided, then f₆ is avoided. Initially, thethirteen communication beams are divide into two blocks of which thereare twelve possible combinations. For each combination, the channelselections can be f₁f₁₁ and f₁₁f₁ such that there are a total oftwenty-four block and channel combinations. Assuming that the kthblock-channel combination has a configuration as follows:

-   -   Block 1: communication beams 0 to b_(k) (0 to N−2) are assigned        to channel C₁; and    -   Block 2: communication beams b_(k)+1 to N−1 (1 to N−1) are        assigned to channel C₂        Then the communication traffic load of channels f₁ and f₁₁ is        the sum of the loads of the communication beams assigned to        those channels as follows:

${L_{f\; 1}^{k}(t)} = {\sum\limits_{f_{1}}{{N_{i\; f\; 1}(t)}\mspace{31mu} {\forall( {i \in f_{1}} )}}}$${L_{f\; 11}^{k}(t)} = {\sum\limits_{f_{11}}{{N_{{if}\; 11}(t)}\mspace{31mu} {\forall( {i \in f_{11}} )}}}$

The peak communication load on the first block for combination k isdenoted by:

PL ₁(k)=max {L ^(k) _(f1)(t)} where t is of the set [0,T]

PL ₂(k)=max {L ^(k) _(f11)(t)} where t is of the set [0,T],

and the peak communication load for the busiest block (e.g., channel)is:

PL _(max)(k)=max {PL ₁(k),PL ₂(k)}

A combination index R with the least peak communication load is thenselected such that PL_(max)(R)=min {PL_(max)(k)} where (0≦k≦71) which isthe combination of channels and beams that minimize the peak load on anychannel. If the peak load on a channel is not less than thePeakLoadLimit, then a three channel assignment can be implemented.

Memory component(s) 818 can maintain routing and signal informationwhich can include transmit power level information, transmit data rateinformation, antenna pointing direction information, weightinginformation, constraints information, null/zero location information,peak location information, quality of service (QoS) information,priority information, lifetime information, frequency information,timing information, user and node authentication information, keep outarea information, etc., that is associated with each sending andreceiving communication channel of the wireless communication system andwithin the multi-beam directed signal system 206. In an implementation,at least some of routing information can be maintained with memorycomponents) 818 within one or more routing tables or similar datastructure(s).

The routing table(s) or similar data structure(s) provide an informationbasis for each routing decision within the wireless communication system(e.g., multi-beam directed signal system 206). By way of example,routing table(s) entries may include all or part of the followinginformation:

-   -   IP address (e.g., IPv6) of a node in the wireless network—e.g.,        as an index,    -   48-bit unique address—e.g., IEEE 802.1 MAC address,    -   Protocol ID—e.g., IEEE 802.11, 802.16.1, etc.,    -   Modulation method,    -   Connection ID (CID) of a node—e.g., as used in an IEEE 802.16.1        MAC,    -   Nominal direction to a node—e.g., one or two dimension,    -   Nominal transmit power level to a node,    -   Nominal received signal strength indicator (RSSI) level from a        node,    -   Nominal channel to transmit on, and perhaps a backup channel,    -   Nominal channel to receive on, and perhaps a backup channel,    -   Nominal transmission data rate, e.g., 6 Mbps-54 Mbps, or as        available,    -   Nominal receive data rate, e.g., 6 Mbps-54 Mbps, or as        available,    -   Known station interference nulls, and    -   Unknown station interference nulls.        In an exemplary implementation, and within the structure of        signal control/coordination logic 304, the routing table(s) are        configured to receive or include data and/or primitives (e.g.,        function calls) from n Internet Protocol (IP) layer and a medium        access control (MAC) layer, and to instruct a physical (PHY)        layer to provide media access through the MAC layer. Therefore,        in some examples, a routing table is more than simply a data        table (or other similar structure) since it may also perform or        otherwise support controlling and/or scheduling functions.

The communication interface(s) 820 can be implemented as any one of aserial, parallel, network, or wireless interface that communicativelycouples the multi-beam directed signal system 206 with other electronicand/or computing devices. For example, the multi-beam directed signalsystem 206 can be coupled with a wired connection (e.g., an input/outputcable) via a communication interface 820 to a network switch thatcommunicates digital information corresponding to a communication signalto a server computing device. Any of the communication interfaces 820can also be implemented as an input/output connector to couple digital,universal serial bus (USB), local area network (LAN), wide area network(WAN), metropolitan area network (MAN), and similar types of informationand communication connections.

The scanning receiver 822 scans each directed communication beam (e.g.,directed communication beams 214 shown in FIGS. 2 and 3) consecutivelyand monitors for client devices and associated information such as thetransmit power of a client device, roaming status, and the many othercommunication factors to update data that is maintained about eachclient device that is in communication via a communication beam. In animplementation, the scanning receiver 822 can be described in twooperating states: a scan mode and a roaming mode. While operating in thescan mode, the scanning receiver 822 periodically scans the thirteencommunication beams on the three channels and collects activityinformation to be maintained with the client device data.

FIG. 9 illustrates an exemplary multi-beam directed signal system 206that includes various components such as medium access controllers(MACs) 900, baseband units (BB) 902, and MAC coordinator logic 904. Themulti-beam directed signal system 206 also includes radio frequency (RF)components 906 such as the left and right transmit antenna boards 800and 802 (shown in FIG. 8), respectively, and the left and right receiveantenna boards 804 and 806, respectively. This example also illustratesthe antenna array 302, the transmit beam-forming network 808 and thereceive beam-forming network 810, and an Ethernet switch and/or router908.

As described in the implementation with reference to FIG. 8, antennaarray 302 (e.g., via antenna assembly 208) is coupled to thebeam-forming networks 808 (transmit) and 810 (receive). The beam-formingnetworks 808 and 810 are coupled to multiple RF components 906(1),906(2), . . . , 906(N). Respective RF components 906(1), 906(2), . . . ,906(N) are each coupled to a respective baseband unit 902(1), 902(2), .. . , 902(N) which are coupled to MAC coordinator logic 904. TheEthernet switch/router 908 is coupled to the multiple MACs 900(1),900(2), . . . , 900(N) which are also each coupled to MAC coordinatorlogic 904.

In operation generally, each MAC 900 is associated with a respectivebaseband unit 902. Although not specifically shown in FIG. 9, eachrespective MAC 900 may also be communicatively coupled to acorresponding baseband unit 902. MAC coordinator logic 904 is configuredto coordinate the activities of the multiple MACs 900 with regard to atleast one non-associated respective baseband unit 902. For example, MACcoordinator logic 904 may forward an instruction to MAC 900(1)responsive, at least partly, to an indicator provided from baseband unit902(2). MAC coordinator logic 904 can be implemented as hardware,software, firmware, and/or some combination thereof.

The Ethernet switch/router 908 is coupled to Ethernet backbone 212 (FIG.2) and is configured to relay incoming packets from Ethernet backbone212 to the appropriate MAC 900 to which they correspond. Ethernetswitch/router 908 is also configured to relay outgoing packets from themultiple MACs 900 to Ethernet backbone 212. Ethernet switch/router 908may be implemented using, for example, a general purpose centralprocessing unit (CPU) and memory. The CPU and memory can handle layer-2Internet protocol (IP) responsibilities, flow control, and so forth.When receiving packets from Ethernet backbone 212, Ethernetswitch/router 908 obtains the destination port for the destination MAC900 address. In this manner, an Ethernet switch and/or router may berealized using software (or hardware, firmware, some combinationthereof, etc.).

The beam-forming networks 808 and 810, in conjunction with antenna array302, form the multiple directed communication beams 214 (FIGS. 2 and 3),A beam-forming network can be implemented as an active or passivebeam-former. Examples of such active and passive beam-formers include atuned vector modulator (multiplier), a Butler matrix, a Rotman lens, acanonical beam-former, a lumped-element beam-former with static orvariable inductors and capacitors, and so forth. Alternatively,communication beams may be formed using full adaptive beam-forming.

As described with reference to FIGS. 8A and 8B, a beam-forming network808 and 810 may include multiple ports for connecting to antenna array302 and additional ports for connecting to the multiple RF components906. One or more active components (e.g., a power amplifier (PA), alow-noise amplifier (LNA), etc.) may also be coupled to the multipleports on the antenna array side of the beam-forming networks 808 and810. Thus, antenna array 302 may be directly or indirectly coupled tothe beam-forming networks 808 and 810.

The beam-forming networks 808 and 810 may include at least “N” parts foreach of the multiple RF components 906(1, 2, N). In an exampleimplementation, each communication beam 214 emanating from antenna array302 corresponds to an RF component 906. Each RF component 906 can beimplemented as a transmit and/or receive signal processor operating atradio frequencies and each RF component 906 can operate at one or morefrequencies, with each frequency corresponding to a different channel.It should be noted that channels may be defined alternatively (and/oradditionally) using a mechanism other than frequency, such as a code, atime slot, a signal node, some combination thereof, and so forth.

As described above, each respective RF component 906(1, 2, . . . , N) iscoupled to a respective baseband unit 902(1, 2, N) and each respectiveMAC 900(1, 2, . . . , N) is associated with a corresponding basebandunit 902(1, 2, N). Although not illustrated in this example or required,each MAC 900 and associated respective baseband unit 902 may be locatedon individual respective electronic cards. Additionally, the respectiveRF component 906 to which each respective baseband unit 902 is coupledmay also be located on the individual respective electronic cards.

Each respective MAC 900 and corresponding baseband unit 902 may beassociated with a different respective access point, such as accesspoints 702(1, 2, . . . , N) (FIG. 7), Each respective RF component 906,along with signal nodes (e.g., ports, communication nodes, etc.) of thebeam-forming networks 808 and 810, and/or antenna array 302, andrespective communication beams 214 may also correspond to the differentrespective access points 702. The MACs 900 are configured to controlaccess to the media that is provided, at least partially, by basebandunits 902. In this case, the media corresponds to the signalstransmitted and/or received via communication beams 214 (FIGS. 2 and 3).These signals can be analog, digital, and so forth. In a describedimplementation, digital signals comprise one or more data packets.

In a packet-based environment, a data packet arriving at the multi-beamdirected signal system 206 (or at access station 102) via a particularcommunication beam 214 from a particular remote client device 202 (FIG.2) is received via the antenna array 302 and the beam-forming networks808 and/or 810. The data packet is processed through a particular RFcomponent 906 and a corresponding baseband unit 902. The data packet isthen forwarded from baseband unit 902 to a corresponding MAC 900 whichfacilitates data packet communication via the Ethernet backbone 212(FIG. 2) by Ethernet switch/router 908. Data packets arriving at themulti-beam directed signal system 206 (or at access station 102) viaEthernet switch/router 908 are transmitted to a remote client device 202and/or 204 via directed communication beam(s) 214 in an oppositecommunication path. The transmission and reception of data packets viadirected communication beams 214, as well as the forwarding of packetswithin the multi-beam directed signal system 206 is controlled at leastpartially by the MACs 900.

In a typical MAC-baseband environment, a MAC controls the associatedbaseband circuitry using input solely from the associated basebandcircuitry. For example, if baseband circuitry indicates to itsassociated MAC that it is receiving a packet, then the associated MACdoes not initiate the baseband circuitry to transmit a packet, which canjeopardize the integrity of the packet being received.

With co-located access points 702 (e.g., as in FIG. 7) and/or co-locatedpairs of MACs 900 and associated baseband units 902, a first accesspoint 702(1) and/or a first MAC 900(1)/baseband unit 902(1) pair areunaware of the condition or state (e.g., transmitting, receiving, idle,etc.) of a second access point 702(2) and/or a second MAC900(2)/baseband unit 902(2) pair, and vice versa. As a result, absentadditional control and/or logic, a data packet being received by thefirst access point 702(1) and/or the first MAC 900(1)/baseband unit902(1) pair can be corrupted (e.g., altered, destroyed, interfered with,rendered unusable for its intended purpose, etc.) by a transmission fromthe second access point 702(2) and/or the second MAC 900(2)/basebandunit 902(2) pair. This corruption may occur even though the packetreception and the packet transmission are effectuated using differentcommunication beams 214(3) and 214(2), respectively, when the receptionand transmission occur on the same channel. Effectively, an incomingdata packet reception via a first communication beam 214 can be renderedunsuccessful by an outgoing data packet transmission via a secondcommunication beam 214 that occurs on the same channel and isoverlapping.

As described above, MAC coordinator logic 904 is coupled to the multiplebaseband units 902(1, 2, . . . , N) and to the multiple MACs 900(1, 2, .. . , N). The MAC coordinator logic 904 is configured to prevent MACs900(1, 2, . . . , N) from generating or otherwise causing a transmissionif at least one and optionally if any of the baseband units 902(1, 2, .. . , N) are receiving. For example, if baseband unit 902(2) indicatesthat it is receiving a data packet, MAC coordinator logic 904 initiatesthat MACs 900(1, 2, . . . , N) refrain from generating or otherwisecausing a data packet transmission during the data packet reception.Factors that can modify, tune, tweak, extend, etc. this data packettransmission restraint may include one or more of the MACs 900 enablingtransmissions on different channel(s) from that of baseband unit 902(2)which is receiving.

More specifically, each baseband unit 902 forwards a correspondingreceive indicator to MAC coordinator logic 904 which monitors thebaseband units 902. The MAC coordinator logic 904 analyzes the receiveindicators to generate constructive receive indicators that arecommunicated, or otherwise provided, to each of the MACs 900. In adescribed implementation, each baseband unit 902 forwards a receiveindicator that reflects whether and/or when a baseband unit 902 iscurrently receiving a signal. Optionally, not physically forwarding anindicator may constitute a receive indicator that reflects no signal isbeing received. After processing the different receive indicators, MACcoordinator logic 904 forwards the same constructive receive indicatorto each MAC 900 based on multiple, and possibly all, receive indicators.The MAC coordinator logic 904 may provide different constructive receiveindicators to at least different subsets of the MACs 900.

The receive indicators forwarded to MAC coordinator logic 904 may becomprised of any one or more different indications from the basebandunits 902. For example, the receive indicators may comprise clearchannel assessment (CCA) or busy/non-busy indications. Alternatively,the receive indicators may comprise indications of signal receptionbased on energy signals, cross-correlation signals, data signals, othertransmit and/or control signals, seine combination thereof, and soforth. Furthermore, a receive indicator may comprise an analog ordigital indication (of one or more bits), the driving of one or morelines, the presentation of one or more messages, some combinationthereof, and so forth.

The MAC coordinator logic 904 is configured to accept the receiveindicators from the baseband units 902 and combine them in some mannerto generate or otherwise produce the constructive receive indicator(s).For example, MAC coordinator logic 904 may “OR” the receive indicatorstogether to generate the constructive receive indicator(s).Consequently, if any receive indicator from baseband units 902 indicatesthat a baseband unit is receiving a signal, then, the constructivereceive indicator indicates to each MAC 900 that a reception isoccurring on a directed communication beam 214 (and/or access point 702)of the multi-beam directed signal system 206. As a result, the MACs 900that are provided with an affirmative constructive receive indicator donot cause their respective associated baseband units 902 to transmit.

The constructive receive indicators provided from MAC coordinator logic904 may be comprised of any one or more different indicationsinterpretable by the MACs 900. For example, the constructive receiveindicators may comprise an indication for one or more predeterminedinputs, such as a CCA or busy/non-busy input of the MACs 900.Alternatively, the constructive receive indicators may be input to adifferent type of do-not-transmit input, a specially-designed input, amessage-capable input, some combination thereof, and so forth.Furthermore, a constructive receive indicator may comprise an analog ordigital indication (of one or more bits), the driving of one or morelines, the presentation of one or more messages, some combinationthereof, and the like.

FIG. 10 further illustrates various components of the multi-beamdirected signal system 206 shown in FIG. 9 which includes the MACs 900,baseband units 902, and MAC coordinator logic 904. In this example, theexemplary multi-beam directed signal system 206 includes thirteen MACs900(1, 2, . . . , 13) and thirteen baseband units 902(1, 2, 13) that areassociated respectively therewith. Thirteen baseband units 902(1, 2, . .. , 13) and thirteen MACs 900(1, 2, 13) are utilized in this exemplarymulti-beam directed signal system 206 to comport with the efficientlyusable communication beams 602(0-6) and 602(10-15) of the exemplary setof communication beams shown in FIG. 6. However, the elements andfeatures described with reference to FIG. 10 are applicable tomulti-beam directed signal systems 206 and/or access stations 102 withmore than r fewer than thirteen MACs 900 and associated baseband units902.

The baseband units 902(1, 2, . . . , 13) are configured to communicatewith MACs 900(1, 2, . . . , 13), and vice versa, directly or indirectlywithout MAC coordinator logic 904 input. Specifically, control data maybe transferred there between which may include, for example, datapackets for wireless communication on communication beams 214 (FIGS. 2and 3), carrier sense multiple access/collision avoidance (CSMA/CA) typeinformation, and so forth. The media access technique in 802.11 is basedon a Carrier Sense Multiple Access (CSMA) operation in which a eachstation transmits only when it determines that no other station iscurrently transmitting. This tends to avoid collisions that occur whentwo or more stations transmit at the same time where a collision wouldtypically require that a transmitted packet be retransmitted.

In this example, the baseband units 902(1, 2, . . . , 13) forwardreceive indicators (1, 2, 13) to MAC coordinator logic 904. The MACcoordinator logic 904 includes a receive indicators combiner 1000 whichmay be comprised of one or more of program coding, a field-programmablegate array, discrete logic gates, and so forth, and which may beimplemented as hardware, software, firmware, and/or some combinationthereof. Receive indicators combiner 1000 combines receive indicators(1, 2, . . . , 13) to generate constructive receive indicators (1, 2, .. . , 13). For example, receive indicators (1, 2, . . . , 13) may becombined using a logical “OR” functionality which ensures that if anyone or more receive indicators of receive indicators (1, 2, 13) isindicating that a signal is being received, then the associatedconstructive receive indicators of constructive receive indicators (1,2, . . . , 13) also indicate that a signal is being received.

The constructive receive indicators (1, 2, . . . 13) are provided orotherwise communicated to MACs 900(1, 2, 13), respectively, so that.MACs 900(1, 2, . . . , 13) do not cause baseband units 902(1, 2, . . . ,13) to transmit a signal while another signal is being received. Thebaseband units 902(1, 2, . . . , 13) and the MACs 900(1, 2, 13) may besegmented or grouped by a characteristic and/or state, such as bywireless communication channels. When segmented or grouped, aconstructive receive indicator of a given segment or group indicates toa MAC that a signal is being received and that no signal shouldtherefore be transmitted when any receive indicator of that givensegment or group indicates that a signal is being received (or whenmultiple receive indicators of that given segment or group indicate thatmultiple signals are being received).

The MAC coordinator logic 904 can be modified, adjusted, expanded, etc.based on any number of different factors that include channel assignmentinformation 1002, receive indicator enable information 1004, timer logic1006, and scanning logic 1008. Although illustrated as separatecomponents, any one or combination of the channel assignment information1002, receive indicator enable information 1004, timer logic 1006,and/or scanning logic 1008 can be implemented together and/or as part ofMAC coordinator logic 904 or as another component of a multi-beamdirected signal system 206.

Channel assignment information 1002 enables receive indicators (1, 2, .. . , 13) to be combined by the receive indicators combiner 1000 on aper-channel basis. As a result, constructive receive indicators (1, 2, .. . , 13) restrain signal transmissions from MAC 900 and baseband unit902 pairs when a signal reception is occurring on the same channel, evenif by a different MAC 900 and baseband unit 902 pair. A downlinked datapacket that is transmitted on one channel while an uplinked data packetis being received on another channel does not usually cause the uplinkeddata packet to be corrupted. On the other hand, a downlinked data packetthat is transmitted on a channel while an uplinked data packet is beingreceived on the same channel does usually cause the uplinked data packetto be corrupted (e.g., indistinguishable, non-communicative, etc.), evenif the transmission and reception occur via different communicationbeams 214 (FIGS. 2 and 3).

Channel assignment information 1002 may be implemented as, for example,a vector that relates each MAC 900 and associated baseband unit 902 toone of two or more channels. Hence, prior to a combination generated bythe receive indicators combiner 1000, each respective receive indicator(1, 2, . . . , 13) can be mapped to a channel segmentation or groupingbased on a wireless communication channel used by a corresponding MAC900 and baseband unit 902 pair.

Receive indicator enable information 1004 provides information forreceive indicators combiner 1000 that stipulates which receiveindicators (1, 2, . . . , 13) are to be used in a combination operationto produce the constructive receive indicators (1, 2, . . . , 13). Thus,certain receive indicators may be excluded from the combinationoperation for one or snore operational considerations. The receiveindicator enable information 1004 may be implemented as, for example, amasking register 1010 that comprises a register with exclusionary bitsfor masking one or more of the receive indicators (1, 2, 13) from acombination operation of the receive indicators combiner 1000. In adescribed implementation, masking register 1010 includes thirteen bitsthat correspond to the thirteen receive indicators (1, 2, . . . , 13),which correspond to the thirteen baseband units 902(1, 2, 13).

Timer logic 1006 can be used for one or more factors and, although onlyshown once, may alternatively be implemented as multiple components inan exemplary multi-beam directed signal system 206 to account formultiple timer functions, or one implementation may be capable ofhandling multiple timer functions. Timer logic 1006 includes a watchdogtimer 1012 and optionally watchdog interrupt enable information 1014.

For a first factor, timer logic 1006 relates to individual receiveindicators (1, 2, . . . , 13). A duration of watchdog timer 1012 is setequal to a maximum data packet duration (e.g., a maximum-allowed lengthof a data packet). Watchdog timer 1012 is started when a particularreceive indicator begins indicating that a signal is being received andstopped when the particular receive indicator ceases indicating that thesignal is being received. If watchdog timer 1012 is not tolled by anindication of signal reception cessation prior to its expiration, thenthe signal being received is likely to not be intended for multi-beamdirected signal system 206. In this case, timer logic 1006 may indicatethat the baseband unit 902 corresponding to the particular receiveindicator is not to be used in a combination operation. This exclusionindication may be effectuated using receive indicator enable information1004 (e.g., by setting a bit in masking register 1010).

For a second factor, timer logic 1006 relates to constructive receiveindicators (1, 2, . . . , 13) on a per-channel basis. A duration ofwatchdog timer 1012 is set with consideration of a temporal thresholdbeyond which a problem or error should be contemplated to have occurredand hence investigated. Watchdog timer 1012 is started when a particularconstructive receive indicator (or indicators) for a given channelbegins indicating that a signal is being received on the given channeland stopped when the particular constructive receive indicator ceasesindicating that the signal is being received on the given channel. Ifwatchdog timer 1012 is not tolled by an indication of signal receptioncessation prior to its expiration, then there is a likelihood that anerror has occurred.

Watchdog interrupt enable information 1014 is used for this secondfactor, and it stipulates which channel(s) (and thus which constructivereceive indicators) are enabled for interruption. If watchdog timer 1012expires and the given channel is enabled in accordance with watchdoginterrupt enable information 1014, an interrupt is generated andprovided to MAC coordinator logic 904 or another component of themulti-beam directed signal system 206.

Scanning logic 1008 may act independently or interactively with any oneor more of channel assignment information 1002, receive indicator enableinformation 1004, and timer logic 1006. For example, scanning logic 1008can scan across communication beams 214 using different channels onreceive to detect which channel or channels have the least or lowestinterference levels. This scanning may occur once, periodically,continuously, and the like. A channel assignment vector or similar forchannel assignment information 1002 may be configured responsive to suchscanning and interference determinations of scanning logic 1008.

As another example, scanning logic 1008 may scan across communicationbeams 214 to detect the presence of other access points (e.g.,non-co-located access points) that are causing interference on a regularor constant basis. The existence of an access point may be inferred byreceiving a basic service set identifier (BSSID) being broadcast byanother access point. When another access point is detected within acoverage area of a particular communication beam 214 (e.g., when anoverlapping subnet is detected), scanning logic 1008 may interact withreceive indicator enable information 1004 to mask out a correspondingreceive indicator from a baseband unit 902 that corresponds to theparticular communication beam 214. As a result, frequent receptions fromthe overlapping subnet do not constantly prevent baseband unit 902 andMAC 900 pairs on the same channel from transmitting.

In an exemplary implementation, multi-beam directed signal system 206can be configured such that the receive indicators (1, 2, 13) correspondto the state of the clear channel assessment (CCA) output as detected bybaseband units 902(1, 2, . . . , 13), and the constructive receiveindicators (1, 2, . . . , 13) correspond to the state of the clearchannel assessment input to MACs 900(1, 2, . . . , 13). Based on thevalues for receive indicators (1, 2, . . . , 13), channel assignmentinformation 1002, and receive indicator enable information 1004, MACcoordinator logic 904 determines the constructive receive indicators (1,2, . . . , 13) for each RF component 906 (FIG. 9) (as provided via MACs900, baseband units 902, etc).

In an exemplary implementation, MAC coordinator logic 904 is configuredto operate such that an indicator “channel_ wide_busy” for each channelis defined, where channel_wide_busy is affirmative (e.g., active) if thereceive indicator from any baseband units operating on that channelindicates that a signal is being received, excluding those basebandunits whose receive indicator enable information is not set (e.g., inmasking register 1010). Further, MAC coordinator logic 904 sets theconstructive receive indicator for a particular MAC 900 and basebandunit 902 pair to affirmative (e.g., busy) if the receive indicator forthat baseband unit 902 indicates affirmative (e.g., busy), or if“channel_wide_busy” for the channel of the particular MAC 900 andbaseband unit 902 pair is affirmative (e.g., active).

FIG. 11 illustrates a state transition diagram 1100 for a MAC controller900 as shown in FIGS. 9 and 10. MAC controller states include Defer1102, BackOff 1104, Idle 1106, TransmissionRTS (TxRTS) 1108, WaitCTS1110, Transmission Data (TxData) 1112, Wait Acknowledgement (WaitACK)114, Receive 1116, Transmission Acknowledgement (TxACK) 1118, andTransmissionCTS (TxCTS) 1120. The state transition diagram 1100 alsoincludes received frame types Data 1126 and RTS 1128, as well asprocedures Transmission okay (TxOK( )) 1122 and Transmission fail(TxFail( )) 1124.

The TxOK( ) procedure 1122 removes bytes transmitted from an outgoingqueue and resets retry counter(s) and a contention window. The TxFail( )procedure 1124 increments a retry counter, checks that the number ofretries has not been exceeded, and increases the contention window. TheReceive state 1116 ends if there is a transmission or check error, ifthe carrier is lost, or when a duration indicated in a header haselapsed. If there is an error, the Defer state 1102 timeout is set toinitiate. If a frame did not have an error and is not addressed to aparticular station, and it's duration field is greater than the currenttimer value, then the timer is set to the value of the frame's durationfield.

At the BackOff state 1104, a backoff counter is decremented every slottime and a backoff count is saved if this state is exited due to achannel becoming busy. When the backoff counter decrements to zero andMAC service data units are queued to transmit, the contention window andretry counts are reset. A MAC service data unit is the payload carriedby a MAC (e.g., in an 802.11 implementation which will typically be an.Ethernet frame). The MAC 900 adds a MAC header and a 32-bit CRC to theMAC service data unit to form a MAC protocol data unit.

Additionally, the state transition diagram 1100 includes variousfunctions that return logical value(s) to control state transitions suchas data( ), short( ), more( ), busy( ), error( ), notforus( ), and nav(). The diagram 1100 also includes PHY indications that initiate a statetransition such as busy, timeout, new, transmission end (txend), andreceive end (rxend). The PHY indications are asynchronous events (e.g.,interrupts) that terminate states for a MAC controller 900. Anindication receive end (rxend) identifies that a receiver has detectedthe end of a frame or an error. An indication transmission end (txend)identifies that a receiver has completed sending a frame. A busyindication is a receiver indication that a channel is busy. A timeoutindication is generated when a transition state timer has expired. A newindication identifies that a new frame has been queued.

A busy( ) function returns a receiver indication that a channel is busy,and an error( ) function indicates that a received frame had a CRCerror. A notforus( ) function indicates that a frame was not addressedto a particular station, and a nay( ) function indicates that a timerhas not expired. A data( ) function indicates that data is queued tosend, and a short( ) function indicates that a MAC protocol data unit isshorter than an RTS Threshold and that there are additional datafragments to be sent from a current MAC controller. A more( ) functionfacilitates obtaining the additional data fragments.

FIG. 12 illustrates an exemplary implementation 1200 of the multi-beamdirected signal system 206 that weighs signals received via antennaarray 302. Communication and/or data transfer signals are received fromsources 1202 (e.g., sources A and B). The signals received from sources1202 are considered desired signals because they are from nodes withinthe wireless routing network. Further, signals such as noise and WLANinterference associated with another external wireless system 1204 arenot desired.

These signals, both desired and undesired, are received via antennaarray 302 and are provided to the signal control and coordination logic304 (shown in FIG. 3) from the receiver/transmitters (Rx/Tx) 824(0),824(1), . . . , 824(N) (also shown in FIG. 8B). In this example, thesignal control and coordination logic 304 includes the scanning receiver822 that is configured to update routing information 1206 with regard tothe received signals. For example, scanning receiver 822 may identifyinformation about different classes of interferers (e.g., known andunknown types) within the routing information 1206. In this example,routing information 1206 includes connection indexed routing table(s)based on identification information, such as address information, CID,and the like. The routing table includes identifiers of the desiredsources and other identifiers for the interferers (“Int”). Further, therouting table includes stored weighting values (w) each associated witha particular signal source 1202 (e.g., sources A and B). Otherinformation such as “keep out” identifiers may also be included in thisexemplary routing table.

A description of the received signal(s) can be stored in the routingtable in the form of the pattern or weighting of the signal(s). In thisexample, a polynomial expansion in z, w(z)=w₀+w₁z+w₂z²+w³+w₄z⁴+ . . .+w_(i)z^(i) can be utilized to establish the values of the weights(w_(i)) to be applied to a weight vector. The routing table(s) may storesuch weighing patterns as a function of θ, or the zeroes of thepolynomial, for example. One advantage of zero storage is that the zerosrepresent directions for communication that should be nulled out toprevent self-interference or interfering with other nodes or possiblyother known wireless communication systems, such as WLAN 1204 that isnot part of the wireless routing network, but is operating within atleast a portion of a potential coverage area 1208 and frequency bands.

The polynomial expansion in z, w(z), and the zeroes may be calculatedfrom each other and each may be stored. Updates can be generatedfrequently (e.g., in certain implementations, about every millisecond),and a zero storage system may be more advantageous in most wirelessnetwork environments because only a few values will change at a giventime. Storing the weighting values will in general require changes toall of the weighting values w(i) when any change in the pattern occurs.Note that w(i) and A(θ) may be expressed as Fourier transform pairs(discrete due to the finite antenna element space). The w(i) isequivalent to a time domain impulse response (e.g., a time domain unitsample response) and the A(θ) is equivalent to the frequency response(e.g., an evaluation of w(z) sampled along a unit circle).

The stored weighting values associated with each connection, datasignal, and/or source are utilized in a weighting matrix 1210 whichoperates to apply the latest weighting values to the received signalsand also to transmitted signals. In this illustrative example,subsequently received signals will be processed using the most recentweighting values in the weighting matrix 1210. Thus, as describedherein, the multi-beam directed signal system 206 is configured tocontrol the transmission amplitude frequency band and directionality ofdata packets to other nodes and assist in reducing the effectsassociated with received noise and interference (e.g., self interferenceand/or external interference). This is accomplished with the signalcontrol and coordination logic 304 within the multi-beam directed signalsystem 206.

FIG. 13 illustrates an exemplary multi-beam directed signal system 206that includes an antenna array 302 and a Butler matrix 1300 implementedas a beam-forming network (e.g., transmit beam-forming network 808and/or receive beam-forming network 810 shown in FIGS. 8A and 8B). Themulti-beam directed signal system 206 also includes multiple signalprocessors (SPs) 1302 and one or more baseband processors (e.g.,baseband units 902 described with reference to FIGS. 9 and 10). Basebandprocessors 902 accept communication signals from and providecommunication signals to the multiple receiver/transmitters 824 (FIG.8B). A separate baseband processor 902 may be assigned to each signalprocessor 1302, or a single baseband processor 902 may be assigned toany number of the multiple signal processors 1302.

Exemplary Butler matrix 1300 is a passive device that forms, inconjunction with antenna array 302, communication beams 214 using signalcombiners, signal splitters, and/or signal phase shifters. Butler matrix1300 includes a first side with multiple antenna ports (designated by“A”) and a second side with multiple transmit and/or receive signalprocessor ports (designated by “Tx/Rx”). The number of antenna ports andtransmit/receive ports indicate the order of the Butler matrix 1300,which in this example, includes sixteen antenna ports and sixteentransmit/receive ports. Thus, Butler matrix 1300 has an order ofsixteen.

Although Butler matrix 1300 is so illustrated, the antenna ports andtransmit/receive ports need not be distributed on separate, much lessopposite, sides of a Butler matrix. Also, although not necessary, Butlermatrices typically have an equal number of antenna ports and transmitand/or receive signal processor ports. Furthermore, although Butlermatrices are typically of an order that is a power of two (e.g., 2, 4,8, 16, 32, 64, . . . , 2^(n)), they may alternatively be implementedwith any number of ports.

The sixteen antenna ports of Butler matrix 1300 are identified orotherwise numbered from A(0, 1, . . . , 15). Similarly, the sixteentransmit/receive ports are numbered from Tx/Rx(0, 1, . . . , 15).Antenna ports A(0-15) are coupled to and populated with sixteen antennaelements 400(0), 400(1), . . . , 400(15), respectively. Likewise,transmit/receive ports Tx/RA(0-15) are coupled to and populated withsixteen signal processors 1302(0), 1302(1), . . . , 1302(15),respectively. These signal processors 1302 are also directly orindirectly coupled to baseband processors 902, It should be noted thatone or more active components (e.g., a power amplifier (PA), a low-noiseamplifier (LIMA), etc.) may also be coupled on the antenna port side ofButler matrix 1300.

In an exemplary transmission operation, communication signals areprovided from baseband processors 902 to the multiple transmit and/orreceive signal processors 1302. The multiple signal processors 1302forward the communication signals to the transmit/receive portsTx/Rx(0-15) of Butler matrix 1300. After signal processing (e.g., signalcombination, signal splitting, signal phase shifting, and the like),Butler matrix 1300 outputs communication signals on the antenna portsA(0-15). Individual antenna elements 400 wirelessly transmit thecommunication signals, as altered by Butler matrix 1300, from theantenna ports A(0-15) in predetermined communication beam patterns. Thecommunication beam patterns are predetermined by the shape, orientation,constituency, etc. of antenna array 302 and by the Butler matrix 1300signal processing. In addition to transmissions, wireless signals suchas wireless communications 106 (FIG. 1) are received responsive to thecommunication beams 214 formed by antenna array 302 in conjunction withButler matrix 1300 in an inverse process.

FIG. 14 further illustrates an exemplary modified Butler matrix 1300 fora complementary beam-forming, post-combining implementation,Complementary beam-forming is a technique to reduce the effect ofcommunication beam nulls and increase sidelobe levels without a severepower penalty to the main beam. This is done to reduce the effect of the“hidden beam”. As described below, increasing the range of 802.11networks without increased transmit power and using standard clients ispossible with adaptive antenna arrays, such as, for example, directionalhigh-gain antennas. Using high gain antennas, it is possible to directthe energy in a given direction and hence increase the range in thatdirection.

Forming directional transmit communication beams has the side effect ofhiding the transmitted energy from some client devices in a CSMA network(i.e., negatively impacting the carrier sense mechanism in the network).A client device measures the energy transmitted from access points andfrom other client devices. If the client device cannot detect thepresence of other transmissions, it attempts to access the medium.Therefore, when directional communication beams are used, many clientdevices detect the medium as idle when in fact it is busy. This has aneffect on the performance of the network and is referred to as the“hidden beam” problem.

In practice, a communication beam (e.g., directional beam) has a mainbeam whose width can be controlled by the size of the antenna aperture,and sidelobes which vary in different directions. However, thesecommunication beams may have nulls in certain directions that affect thewireless network with a hidden beam. Since a given receiver's energydetect threshold is usually lower than it's decoding threshold, it ispossible to direct a high power signal towards an intended client deviceand yet ensure a minimum transmit power towards other clients in thenetwork so that the signal may be detected by other clients.

Complementary beam-forming ensures a minimum transmit power in alldirections while preserving the shape of the main communication beam.The complementary beam-forming techniques also ensure that multipletransmit beams in arbitrary directions are complemented by another beamin all other directions. The complementary beam does not interfere withthe intended beams and increases the probability that other users in thenetwork can detect the signal.

The modified Butler matrix 1300 includes the antenna ports 400(0, 1, . .. , N−1, N) and a gain mechanism 1400 configured to modify the signal atoutput port 400(0). A transmit signal is input to a corresponding inputport of the Butler matrix and, in conjunction with the gain mechanism1400, a complementary beam is formed due to the increase in gain. Theresult is a directional communication beam from the antenna in a givendirection. A complementary beam-forming, pre-combining implementationcan also be implemented.

Mathematically, a complementary beam-forming, post-combiningimplementation may be described as:

$y_{i} = \{ {{\begin{matrix}{\gamma \; y_{i}} & {i = 0} \\y_{i} & {\gamma \geq 1}\end{matrix}\mspace{14mu} 0} \leq i \leq {N - 1}} $

where y_(i) is the power applied to antenna element i and γ is the gainvalue contained in the gain mechanism 1400. To ensure the same outputpower as with no complementary beam-forming, the output voltage on allof the Butler matrix ports can be adjusted by a scaling factor:

$G_{s} = \sqrt{\frac{N}{\gamma^{2} + N - 1}}$

The power for the main communication beam will then be:

${\Delta \; P} = \frac{( {\gamma + N - 1} )^{2}}{N( {\gamma^{2} + N - 1} )}$

or stated in terms of dB:

${\Delta \; P_{d\; B}} = {10\; \log \{ \frac{( {\gamma + N - 1} )^{2}}{N( {\gamma^{2} + N - 1} )} \}}$

For example, for a sixteen element antenna array 302, if γ=3.5, then thepower loss is approximately one dB.

FIG. 15 illustrates a graph 1500 depicting the signal level output (dB)for certain ports of the modified Butler Matrix 1300 shown in FIG. 14.Graph 1500 depicts the shape of a transmit communication beam 1502without complementary beam-forming and a transmit communication beam1504 with complementary beam-forming applied. In this example, thetransmit communication beam is derived from a signal at port 400(0) ofButler Matrix 1300. As shown, the output with complementary beam-forming(e.g., transmit communication beam 1504) has higher sidelobes in alldirections and removes all of the deep nulls except for the nulls on themain communication beam. The peak power of the main communication beamis approximately one dB lower than that without complementarybeam-forming.

FIG. 16 illustrates a transition diagram 1600 for a roaming clientdevice that transitions from one communication location within awireless network system to another. For example, client device 202 (FIG.2), while in wireless communication with access station 102 via directedcommunication beam 214(1) may roam (e.g., move, relocate, transition,etc.) such that communication with access station 102 would befacilitated via directed communication beam 214(2). A client deviceinitially associates to one directed signal of the multi-beam directedsignal system 206 by selecting the signal (e.g., communication beam)with the best signal at the time of association. However, because theclient device may be portable and/or the wireless environment may change(e.g., due to device transitions, interference, etc.), the initiallyselected directed signal may not provide a continuous, or the best,communication channel over which to communicate information (e.g., inthe data packets) and hence the client may have to roam and/or beassociated with another directed communication beam.

Roaming is dependent on client device implementation, is initiated by aclient device, and may not be directly controlled by the multi-beamdirected signal system 206. In most commercially available clientdevices, roaming is triggered when the channel quality (SNR) falls belowa threshold. The channel quality assessment (SNR measurement) is basedon received strength of a directed communication beam. To ensure that aclient device is associated with the best signal, the multi-beamdirected signal system 206 directs the client device to roam to thedirected communication beam with the best signal quality using abeam-switching algorithm.

Additionally, to ensure seamless roaming between communication beams,the multi-beam directed signal system 206 implements Inter-Access PointProtocol (IAPP) which is defined by IEEE 802.11f to supportinteroperability, mobility, handover messaging between directedcommunication beams 214, and coordination between access stations 102 ina wireless communications environment. Beam-switching can be implementedby the multi-beam controller 816 (FIG. 8B) in the multi-beam directedsignal system 206 to ensure that client devices are associated with thedirected communication beam 214 having the best signal level and IAPP toensure client-initiated seamless roaming.

The beam-switching algorithm disassociates a client device once it movesout of an associated main communication beam. However, such movement ofa client device is difficult to detect in the wireless environment anddisassociation may result in data packet loss and a long associationprocedure. The effect is particularly significant for client deviceslocated between adjacent directed communication beams. Hence, thebeam-switching algorithm will disassociate a client device when there isa determinable difference between signal qualities on differentcommunication beams.

With reference to FIG. 16, a client device may be described as being ina monitor state 1602, a correct beam test state 1604, and a force roamstate 1606. In the monitor state 1602, a client device is associatedwith a directed communication beam 214 while the multi-beam directedsignal system 206 (e.g., access station 102) continues to sample andcollect receive strength signal indications (RSSI) values for each datapacket received from the client device. The multi-beam controller 816recalculates a new measure identified as a smoothed RSSI value(SmoothedRSSIValue) over an RSSI window size (RSSIWindowSize) andcompares it to an RSSI lower control limit threshold(RSSILowerControlLimit).

In the correct beam test state 1604, the scanning receiver 822 measuresthe RSSIs and calculates a smoothed RSSI value (SmoothedRSSIValue) forthe client device on each of the adjacent ports (e.g., communicationbeams). Samples of the RSSI window size (RSSIWindowSize) for the twoadjacent ports are averaged and compared to the same parameter for thecurrent communication beam to determine the best, or mast effective,communication beam. In the force roam state 1606, the client device istemporarily disassociated so that it cannot associate to the currentdirected communication beam.

An association transition 1608 to the correct beam test state 1604occurs when a client device associates a directed communication beam214. From the correct beam test state 1604, a correct beam transition1610 indicates that a current communication beam is the bestcommunication link between the client device and the multi-beam directedsignal system. New RSSI values are sampled and a new lower control limit(LowerControlLimit) is recalculated. A scan timeout transition 1612 fromthe correct beam test state 1604 indicates that the scanning receiver822 has been monitoring the adjacent communication beams for more than aroaming scan timeout duration (RoamingScanTimeout) without any decisionabout the correct beam.

From the monitor state 1602, a sample RSSI transition 1614 indicatesthat the smoothed RSSI value (SmoothedRSSIValue) and the RSSI lowercontrol limit (RSSILowerControlLimit) are re-calculated. A smoothed RSSIdrop transition 1616 from the monitor state 1602 drops the smoothed RSSIvalue (SmoothedRSSIValue) to an RSSI lower control limit(RSSILowerControlLimit). A wrong beam transition 1618 from the correctbeam test state 1604 indicates a better communication beam is identifiedthat has an RSSI that exceeds the RSSI of the current communication beamby a signal drop threshold dB (SignalDropThreshold). The client deviceis disassociated from the current communication beam and a timeouttransition 1620 occurs after a roaming time out (RoamingTimeOut). Thestate information corresponding to the client device is then removed(e.g., deleted, discarded, etc.).

The lower control limit parameter (LowerControlLimit) is calculatedusing both the mean and the standard deviation of RSSI as follows:

${LowerControlLimit} = {\overset{\_}{RSSI} - {2\; \sigma}}$${RSSI} = {{\frac{1}{N}{\sum\limits_{i = 0}^{N - 1}{{RSSI}_{i}\mspace{31mu} N}}} = {{RSSIWindow}\mspace{14mu} {Size}\mspace{14mu} {in}\mspace{14mu} {frames}}}$$\sigma = \sqrt{\frac{1}{N}{\sum\limits_{i = 0}^{N - 1}( {{RSSI}_{i} - {\overset{\_}{ {RSSI} )}}^{2}} }}$

The RSSI_(i) is the RSSI value reported for frame i. The N−1th frame isthe most recent frame. The smoothed RSSI value (SmoothedRSSIValue (S))is calculated when RSSI values are sample when a data packet isreceived. The smoothed RSSI value is calculated asS_(j)=0.1·RSSI_(j)+0.9·S_(j-1). This value is then compared to the lowercontrol limit (LowerControlLimit) and if it is larger than the limit,the client device enters the correct beam test state 1604. The IAPPseamless roaming enables seamless client-initiated roaming betweencommunication beams within an antenna panel, between antenna panels, andbetween an antenna panel and third party access points (e.g., accessstations, multi-beam directed signal system, etc.),

Methods for directed wireless communication may be described in thegeneral context of computer-executable instructions. Generally,computer-executable instructions include routines, programs, objects,components, data structures, and the like that perform particularfunctions or implement particular abstract data types. Methods fordirected wireless communication may also be practiced in distributedcomputing environments where functions are performed by remoteprocessing devices that are linked through a communications network. Ina distributed computing environment, computer-executable instructionsmay be located in both local and remote computer storage media,including memory storage devices.

FIG. 17 illustrates a method 1700 for directed wireless communication.The order in which the method is described is not intended to beconstrued as a limitation, and any number of the described method blockscan be combined in any order to implement the method. Furthermore, themethod can be implemented in any suitable hardware, software, firmware,or combination thereof.

At block 1702, a directed wireless communication is generated for datacommunication with a client device. At block 1704, the directed wirelesscommunication is received at an antenna assembly, and at block 1706, adirected communication beam is emanated for the data communication withthe client device. For example, the multi-beam directed signal system206 (shown in FIG. 2) generates a directed wireless communication fordata communication with client device 202. Antenna assembly 208 receivesthe generated wireless communication and emanates a directedcommunication beam 214(1) for the data communication with client device202. In an embodiment, the directed communication beam can be emanatedfrom two or more antenna elements of the antenna assembly as anelectromagnetic signal that includes transmission peaks andtransmissions nulls within a coverage area of the directed communicationbeam 214(1).

At block 1708, the data communication is transmitted to the clientdevice via the directed communication beam. At block 1710, a seconddirected communication beam is emanated for data communication receptionfrom a second client device, and at block 1712, a second datacommunication is received from the second client device via the seconddirected communication beam. For example, an additional directedcommunication beam 214(N) can be emanated from antenna assembly 208 fordata communication reception from client device 204. The datacommunication transmission (at block 1708) can be controlled so as notto interfere with receiving the second data communication (at block1712) and optionally, transmitting the data communication and receivingthe second directed data communication is simultaneous.

FIG. 18 illustrates a method 1800 for directed wireless communication.The order in which the method is described is not intended to beconstrued as a limitation, and any number of the described method blockscan be combined in any order to implement the method. Furthermore, themethod can be implemented in any suitable hardware, software, firmware,or combination thereof.

At block 1802, directed wireless communication is coordinated withclient devices via directed communication beams emanated from an antennaassembly. For example, wireless communications are coordinated by thesignal control and coordination logic 304 (shown in FIG. 3) with clientdevices 202 and 204 (FIG. 2) via directed communication beams 214(1) and214(N), respectively, which are emanated from antenna assembly 208. Adirected communication beam can be emanated as an electromagnetic signalthat includes transmission peaks and transmission nulls within acoverage area of the directed communication beam. Further, energy can betransmitted on a side lobe of a directed communication beamcorresponding to a first client device such that a second client devicewill detect the side lobe energy and recognize that a data communicationtransmission is being emanated to the first client device via thedirected communication beam.

The directed wireless communication can be coordinated such that onlyclient device 202 receives a first directed wireless communication viacommunication beam 214(1), and such that only client device 204 receivesa second directed wireless communication via communication beam 214(N).Coordinating directed wireless communication can include simultaneousdata communication transmission to client device 202 via directedcommunication beam 214(1) and a data communication reception from clientdevice 204 via directed communication beam 214(N). Further, the datacommunication transmission is coordinated so as not to interfere withthe data communication reception.

At block 1804, data communication transmissions are routed through atransmit beam-forming network to antenna elements of the antennaassembly such that a data communication transmission is communicated toa client device via a directed communication beam. At block 1806, thedirected communication beams are monitored for data communicationreceptions from the client devices. At block 1808, data communicationreceptions are received through a receive beam-forming network from theantenna elements of the antenna assembly such that a data communicationreception is received from a client device via a directed communicationbeam. For example, a data communication reception can be received from aclient device with scanning receiver 822 (shown in FIG. 8B).

At block 1810, a determination is made as to which of multiple channelsprovides acceptable data communication transmission and/or receptionwith a client device. At block 1812, information is maintainedcorresponding to one or more of the client devices. The information caninclude a transmit power level, a data transmit rate, an antennadirection, quality of service data, and timing data. Further,coordinating a directed wireless communication with a client device (asdescribed in block 1802) can be based on the information that ismaintained (at block 1812).

FIG. 19 illustrates a method 1900 for directed wireless communication.The order in which the method is described is not intended to beconstrued as a limitation, and any number of the described method blockscan be combined in any order to implement the method. Furthermore, themethod can be implemented in any suitable hardware, software, firmware,or combination thereof.

At block 1902, a client device is associated with a directedcommunication beam. For example, a portable client device 202 (shown inFIG. 2) is associated with communication beam 214(1) (shown in FIGS. 2and 3). At block 1904, signal strength indications are received for datapackets received from the client device via the directed communicationbeam. At block 1906, a signal strength average for the client device iscalculated from the received signal strength indications.

At block 1908, adjacent signal strength indications are sampled for anadjacent directed communication beam. At block 1910, a second signalstrength average is calculated for the adjacent directed communicationbeam. For example, signal strength indications are sampled for anadjacent directed communication beam 214(2) (shown in FIGS. 2 and 3),and a signal strength average is calculated for the adjacent directedcommunication beam 214(2).

At block 1912, the signal strength average is compared to the secondsignal strength average and a determination is made as to which providesa more effective, or better, communication link. If the second signalstrength average does not indicate that the adjacent directedcommunication beam would provide a better communication link than thedirected communication beam (i.e., no from block 912), then the clientdevice association with the initial directed communication beam ismaintained at block 914.

If the second signal strength average indicates that the adjacentdirected communication beam would provide a better communication linkthan the directed communication beam (i.e., no from block 912), then theclient device is disassociated with the directed communication beam atblock 916. At block 918, the client device is reassociated with theadjacent directed communication beam. The method 1900 can then continueand be reiterated from block 1902. Additionally, the method 1900 can beimplemented for any number of client devices in wireless communicationwith a directed wireless communication system.

Although wireless communication system(s) have been described inlanguage specific to structural features and/or methods, it is to beunderstood that the subject of the appended claims is not necessarilylimited to the specific features or methods described. Rather, thespecific features and methods are disclosed as exemplary implementationsof wireless communication system(s).

1-38. (canceled)
 39. A method, comprising: routing data communicationtransmissions through a transmit beam-forming network to antennaelements of an antenna assembly such that a data communicationtransmission is communicated to a first client device via a firstdirected communication beam; receiving data communication receptionsthrough a receive beam-forming network from the antenna elements of theantenna assembly such that a data communication reception is receivedfrom a client device via a second directed communication beam; andtransmitting energy on a side lobe of the first directed communicationbeam corresponding to the first client device such that the secondclient device will detect the energy on the side lobe to determine thatthe data communication transmission is directed to the first clientdevice via the first directed communication beam. 40.-63. (canceled) 64.The method of claim 39, further comprising: receiving a datacommunication reception from the first client device with a scanningreceiver; and determining which of multiple channels provides acceptabledata communication transmission and reception with the first clientdevice.
 65. The method of claim 39, further comprising: monitoring thesecond directed communication beam for the data communication receptionfrom the second client device.
 66. The method of claim 39, furthercomprising: maintaining information corresponding to the first clientdevice, wherein the information includes at least one of a transmitpower level, a data transmit rate, an antenna direction, quality ofservice data, and timing data, and wherein the coordinating the directedwireless communication includes coordinating with the first clientdevice based on the maintained information.
 67. The method of claim 39,wherein the first directed communication beam is an electromagneticsignal that includes transmission peaks and transmission nulls within acoverage area of the first directed communication beam.
 68. The methodof claim 39, further comprising: determining when the first directedcommunication beam is ineffective for the data communicationtransmission to the first client device; and routing the datacommunication transmission to the first client device via anotherdirected communication beam.
 69. The method of claim 39, wherein thecoordinating the directed wireless communication includes coordinatingso that only the first client device will receive the directed wirelesscommunication via the first directed communication beam, and that onlythe second client device will receive another directed wirelesscommunication via a third directed communication beam.
 70. The method ofclaim 39, wherein the coordinating the directed wireless communicationincludes coordinating the data communication transmission to the firstclient device via the first directed communication beam and the datacommunication reception from the second client device via the seconddirected communication beam.
 71. The method of claim 39, wherein thecoordinating the directed wireless communication includes coordinatingthe data communication transmission to the first client device and thedata communication reception from the second client device such that thedata communication transmission does not interfere with the datacommunication reception.
 72. A non-transitory computer-readable mediacomprising computer executable instructions that, when executed, directa wireless communication system to: route data communicationtransmissions through a transmit beam-forming network to antennaelements of an antenna assembly such that a data communicationtransmission is communicated to a first client device via a firstdirected communication beam; receive data communication receptionsthrough a receive beam-forming network from the antenna elements of theantenna assembly such that a data communication reception is receivedfrom a second client device via a second directed communication beam;and transmit energy on a side lobe of the first directed communicationbeam corresponding to the first client device such that the secondclient device will detect the energy on the side lobe to determine thatthe data communication transmission is directed to the first clientdevice via the first directed communication beam.
 73. The non-transitorycomputer-readable media of claim 72, further comprising computerexecutable instructions that, when executed, direct the wirelesscommunication system to: receive the data communication reception fromthe first client device with a scanning receiver; and determine which ofmultiple channels provides acceptable data communication transmissionand reception with the first client device.
 74. The non-transitorycomputer-readable media of claim 72, further comprising computerexecutable instructions that, when executed, direct the wirelesscommunication system to: monitor the second directed communication beamfor the data communication reception from the second client device. 75.The non-transitory computer-readable media of claim 72, furthercomprising computer executable instructions that, when executed, directthe wireless communication system to: maintain information correspondingto the first client device, wherein the information includes at leastone of a transmit power level, a data transmit rate, an antennadirection, quality of service data, and timing data; and coordinate thedirected wireless communication with the first client device based onthe maintained information.
 76. The non-transitory computer-readablemedia of claim 72, further comprising computer executable instructionsthat, when executed, cause the first directed communication beam as anelectromagnetic signal to: generate transmission peaks and transmissionnulls within a coverage area of the first directed communication beam.77. The non-transitory computer-readable media of claim 72, furthercomprising computer executable instructions that, when executed, directthe wireless communication system to: generate the first directedcommunication beam as an electromagnetic signal that includes a signaltransmission peak within a first coverage area and a signal transmissionnull within a second coverage area; and generate a third directedcommunication beam as a second electromagnetic signal that includes asecond signal transmission peak within the second coverage area and asecond signal transmission null within the first coverage area.
 78. Thenon-transitory computer-readable media of claim 72, further comprisingcomputer executable instructions that, when executed, direct thewireless communication system to: determine when the first directedcommunication beam is ineffective for the data communicationtransmission to the first client device; and route the datacommunication transmission to the first client device via anotherdirected communication beam.
 79. The non-transitory computer-readablemedia of claim 72, further comprising computer executable instructionsthat, when executed, direct the wireless communication system to:coordinate so that only a first client device receives the directedwireless communication via the first directed communication beam, andthat only the second client device receives another directed wirelesscommunication via a third directed communication beam.
 80. Thenon-transitory computer-readable media of claim 72, further comprisingcomputer executable instructions that, when executed, direct thewireless communication system to: coordinate the data communicationtransmission to the first client device via the first directedcommunication beam and the data communication reception from the secondclient device via the second directed communication beam.
 81. Thenon-transitory computer-readable media of claim 72, further comprisingcomputer executable instructions that, when executed, direct thewireless communication system to: coordinate the data communicationtransmission to the first client device and the data communicationreception from the second client device such that the data communicationtransmission does not interfere with the data communication reception.82. A method, comprising: routing data communication transmissionsthrough a transmit beam-forming network to antenna elements of anantenna assembly such that a data communication transmission iscommunicated to a first client device via a first directed communicationbeam and a null is directed in a particular direction to maximize powerand minimize interference from the first directed communication beam;receiving data communication receptions through a receive beam-formingnetwork from the antenna elements of the antenna assembly such that adata communication reception is received from a second client device viaa second directed communication beam; and transmitting energy on a sidelobe of the first directed communication beam corresponding to the firstclient device such that the second client device will detect energy onthe side lobe to determine that the data communication transmission isbeing directed to the first client device via the first directedcommunication beam.